Lead frame, resin-encapsulated semiconductor device, and method of producing the same

A method for producing a resin-encapsulated semiconductor device, comprising:

• using a lead frame that includes a frame and a plurality of inner leads that extend inward from the frame, each of the inner leads having a protruded portion provided on a surface of an external side portion thereof, the protruded portion being protruded in a thickness direction, together with a first semiconductor chip and a second semiconductor chip, the first semiconductor chip having a first electrode group composed of electrodes arranged in its peripheral portion and a second electrode group composed of electrodes arranged inward relative to the first electrode group, the second semiconductor chip being smaller in size than the first semiconductor chip and having a group of electrodes;
• forming first conductive bumps on the electrodes of the first electrode group of the first semiconductor chip, and forming second conductive bumps on the electrodes of the second semiconductor chip;
• stacking the second semiconductor chip on a surface of the first semiconductor chip, and electrically connecting the electrodes of the second electrode group of the first semiconductor chip with the second conductive bumps on the second semiconductor chip;
• applying a molding sheet so as to be in close contact with surfaces of the protruded portions;
• electrically connecting the first conductive bumps with internal portions of the respective inner leads, the internal portions being positioned inward relative to the protruded portions;
• encapsulating a region including surfaces of the first and second semiconductor chips and the first and second conductive bumps with an encapsulating resin, with the frame and the protruded portions of the inner leads being exposed;
• removing the frame from the encapsulated structure;
• and
• forming external electrodes on surfaces of the protruded portions so that tip ends of the external electrodes are protruded relative to a back face of the first semiconductor chip.